The present invention relates to a method of extracting the contour of an object region from an image, a method of extracting an object from an image, and a video transmission system using the object extraction method.
A technique of extracting an object region from an image can be effectively used for a process of replacing the background with another image. In this case, if the region of a to-be-extracted object as a target object is not properly obtained, a high-quality composite image cannot be obtained.
When the rough shape of an object is obtained in advance by some method, a technique is required, which obtains an object region with a higher precision on the basis of the rough shape. As one of such techniques, the present inventors have proposed the technique disclosed in Takashi IDA and Yoko SAMBONSUGI, “Object Contour Fitting Using Self-Affine Mapping”, Proceedings of the 5th Symposium on Sensing via Image Information, C-15, pp. 115-120, June 1999). This technique uses self-affine mapping.
According to a technique using this self-affine mapping, the rough shape of a provisionally provided to-be-extracted object, i.e., the contour of provisionally provided shape data, can be matched to the contour of a correct object region. In this technique, however, the computation amount for a similar block search is large, and it is difficult to extract a target image part from an image at a high speed. For this reason, this technique needs to be further improved to be applied to moving images and the like.